U.S. patent number 8,864,479 [Application Number 13/319,440] was granted by the patent office on 2014-10-21 for multi-stage scroll machine.
This patent grant is currently assigned to Danfoss Commercial Compressors. The grantee listed for this patent is Patrice Bonnefoi, Pierre Ginies, Stephane Watts. Invention is credited to Patrice Bonnefoi, Pierre Ginies, Stephane Watts.
United States Patent |
8,864,479 |
Watts , et al. |
October 21, 2014 |
Multi-stage scroll machine
Abstract
A machine having two volute casings describing an orbital
relative movement, one of the volute casings being fitted with at
least one scroll and the other volute casing being equipped with at
least two scrolls, the various scrolls delimiting a first series of
variable-volume chambers belonging to a first compression or
expansion stage, and a second series of variable-volume chambers
belonging to a second compression or expansion stage, each stage
having a high-pressure fluid passage and low-pressure fluid
passage. A portion of the low-pressure fluid passage of the second
stage is designed to open into one of the chambers of the second
stage and is further away from the zone of convergence of the
scrolls delimiting the variable-volume chambers of the second stage
than a portion of the high-pressure fluid passage of the first
stage that is designed to open into one of the chambers of the
first stage.
Inventors: |
Watts; Stephane (Lyons,
FR), Bonnefoi; Patrice (Saint Didier au Mont D'Or,
FR), Ginies; Pierre (Sathonay Village,
FR) |
Applicant: |
Name |
City |
State |
Country |
Type |
Watts; Stephane
Bonnefoi; Patrice
Ginies; Pierre |
Lyons
Saint Didier au Mont D'Or
Sathonay Village |
N/A
N/A
N/A |
FR
FR
FR |
|
|
Assignee: |
Danfoss Commercial Compressors
(Reyrieux, FR)
|
Family
ID: |
41651529 |
Appl.
No.: |
13/319,440 |
Filed: |
June 29, 2010 |
PCT
Filed: |
June 29, 2010 |
PCT No.: |
PCT/FR2010/051351 |
371(c)(1),(2),(4) Date: |
December 30, 2011 |
PCT
Pub. No.: |
WO2011/001100 |
PCT
Pub. Date: |
January 06, 2011 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20120100025 A1 |
Apr 26, 2012 |
|
Foreign Application Priority Data
|
|
|
|
|
Jun 30, 2009 [FR] |
|
|
09 54437 |
|
Current U.S.
Class: |
418/55.1; 418/15;
418/180 |
Current CPC
Class: |
F04C
23/001 (20130101); F04C 18/0276 (20130101); F04C
18/0261 (20130101); F04C 23/008 (20130101); F04C
27/005 (20130101) |
Current International
Class: |
F01C
1/02 (20060101); F01C 1/063 (20060101); F04C
18/00 (20060101); F04C 2/00 (20060101); F03C
4/00 (20060101); F01C 21/00 (20060101); F03C
2/00 (20060101) |
Field of
Search: |
;418/55.1,5-11,54-59 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
2 400 625 |
|
Mar 1979 |
|
FR |
|
A-09-329092 |
|
Dec 1997 |
|
JP |
|
Other References
International Search Report issued in International Patent
Application No. PCT/FR2010/051351 dated Jul. 28, 2011. cited by
applicant.
|
Primary Examiner: Bomberg; Kenneth
Assistant Examiner: Wan; Deming
Attorney, Agent or Firm: Oliff PLC
Claims
The invention claimed is:
1. A multi-stage scroll machine intended to compress and/or expand
a fluid, comprising: first and second volute casing describing an
orbital relative movement, the first volute casing being equipped
with at least one scroll and the second volute casing being
equipped with at least one first scroll and at least one second
scroll, the at least one first scroll of the second volute casing
being engaged in the scroll of the first volute casing so as to
delimit at least a first series of variable-volume chambers
belonging to a first compression or expansion stage, and the at
least one second scroll of the second volute casing being engaged
in the scroll of the first volute casing so as to delimit at least
one second series of variable-volume chambers belonging to a second
compression or expansion stage, each compression or expansion stage
comprising at least one high-pressure fluid passage arranged to
open into at least one of the chambers of the respective stage and
at least one low-pressure fluid passage arranged to open into at
least one of the chambers of the respective stage, the
high-pressure fluid passage of the first stage and the
high-pressure fluid passage of the second stage being configured so
that the fluid passing through the high-pressure fluid passage of
the first stage has a lower pressure than that of the fluid passing
through the high-pressure fluid passage of the second stage or, the
lower-pressure fluid passage of the first stage and the
low-pressure fluid passage of the second stage being configured so
that the fluid passing through the low-pressure fluid passage of
the first stage has a pressure lower than that of the fluid passing
through the low-pressure fluid passage of the second stage, wherein
a portion of the low-pressure fluid passage of the second stage
that is arranged to open into at least one of the chambers of the
second stage is further from a first convergence zone of the
scrolls delimiting the variable-volume chambers of the second stage
than a portion of the high-pressure fluid passage of the first
stage that is arranged to open into at least one of the chambers of
the first stage, the first convergence zone being located at a
center portion of the first volute casing; and wherein the at least
one first scroll and the at least one second scroll of the second
volute overlap one another so that, according to at least one
radial cross-section of the second volute casing along a radius in
which the at least one first scroll and the at least one second
scroll overlap, at least one alternation of the at least one first
scroll and the at least one second scroll of the second volute
casing is achieved from a second convergence zone of the at least
one first scroll and the at least one second scroll of the second
volute casing, the second convergence zone being located at a
center portion of the second volute casing.
2. The machine according to claim 1, wherein the variable-volume
chambers of at least one of the stages have a different height from
that of the variable-volume chambers of the other stages.
3. The machine according to claim 1, wherein at least one of the
scrolls of the second volute casing has a different height from
that of the other scrolls of the second volute casing.
4. The machine according to claim 1 wherein the first volute casing
and one of the scrolls of the second volute casing are configured
so that axial play exists between the latter parts, and said scroll
of the second volute casing includes, on its face oriented toward
the first volute casing and on at least a portion of its length, a
sealing segment.
5. The machine according to claim 1, wherein at least one of the
scrolls of the second volute casing has a different thickness from
that of the other scrolls of the second volute casing.
6. The machine according to claim 1, wherein at least one of the
scrolls of the second volute casing has a longitudinally variable
thickness.
7. The machine according to claim 1, further comprising a
connecting member configured to connect the high-pressure fluid
passage of the first stage and the low-pressure fluid passage of
the second stage, on the one hand, and heater or cooler arranged to
heat or cool the fluid flowing between the high-pressure fluid
passage of the first stage and the low-pressure fluid passage of
the second stage, on the other hand.
8. The machine according to claim 1, wherein each scroll of the
second volute casing partially delimits the variable-volume
chambers of a single stage.
9. The machine according to claim 8, wherein the outer end of the
scroll of the first volute casing and the outer end of the at least
one first scroll of the second volute casing partially delimiting
the variable-volume chambers of the first stage are situated
asymmetrically relative to the convergence zone of the scrolls
delimiting the variable-volume chambers of the second stage, and in
that the balancing means include a portion of the scroll of the
first volute casing extending between a point diametrically
opposite the outer end of the scroll of the second volute casing
partially delimiting the variable-volume chambers of the first
stage relative to the convergence zone of the scrolls delimiting
the variable-volume chambers of the second stage and the outer end
of the scroll of the first volute casing.
10. The machine according to claim 1, wherein the scroll machine is
a scroll compressor, in that the low-pressure fluid passages of the
different stages are fluid intake passages, in that the
high-pressure fluid passages of the different stages are fluid
discharge passages, and in that the fluid is intended to be
compressed successively in the first stage and in the second
stage.
11. The machine according to claim 10, wherein at least one of the
stages comprises two variable-volume chambers, called outer chamber
and inner chamber, delimited inwardly and outwardly, respectively,
by one of the scrolls of the second volute casing and arranged to
open into the high-pressure fluid passage of the corresponding
stage, and in that the machine comprises pressure balancing means
configured so that the pressure of the fluid in the outer chamber,
before it is put in communication with the high-pressure fluid
passage of the corresponding stage, is substantially equal to the
pressure of the fluid in the inner chamber before it is put in
communication with the high-pressure fluid passage of the
corresponding stage.
12. The machine according to claim 11, wherein the pressure
balancing means include a protrusion extending from the inner
surface of the scroll of the first volute casing and situated at
the high-pressure fluid passage of the corresponding stage.
13. The machine according to claim 1, wherein the scroll machine is
a scroll expansion machine, in that the low-pressure fluid passages
of the different stages are fluid discharge passages, in that the
high-pressure fluid passages of the different stages are fluid
intake passages, and in that the fluid is intended to be expanded
successively in the second stage and in the first stage.
14. The machine according to claim 1, wherein the first volute
casing is fixed and the second volute casing is mobile.
Description
The present invention relates to a multi-stage scroll machine
intended to compress and/or expand a fluid.
Such a scroll machine is in particular known from document FR 2 400
625, which describes a scroll machine comprising first and second
volute casings describing an orbital relative movement, the first
volute casing being equipped with at least one scroll and the
second volute casing being equipped with at least two scrolls, the
scrolls of the second volute casing being engaged in the scroll of
the first volute casing so as to delimit at least a first series of
variable-volume chambers belonging to a first compression or
expansion stage, and at least a second series of variable-volume
chambers belonging to a second compression or expansion stage, each
compression or expansion stage comprising at least one
high-pressure fluid passage designed to open into one of the
chambers of the respective stage and at least one low-pressure
fluid passage designed to open into one of the chambers of the
respective stage.
When such a machine is configured to operate as a compressor, a
cooling device can be positioned between the high-pressure fluid
passage of the first stage and the low-pressure fluid passage of
the second stage so that the fluid compressed in the first
compression stage is cooled before being conveyed toward the second
compression stage.
Such a configuration makes it possible to prevent the compressed
fluid discharged from the second compression stage from reaching an
excessively high discharge temperature.
One drawback of this type of scroll machine lies in the fact that
the compressed and cooled fluid that is conveyed in the second
compression stage is heated by the compressed fluid that is
discharged from the first compression stage, due to the proximity
of the high-pressure fluid passage of the first stage and the
low-pressure fluid passage of the second stage.
As a result, it is not easy to obtain a compressed fluid having a
low discharge temperature.
Furthermore, when the fluid to be compressed is a gas, this heating
of the gas to be compressed causes an increase in the temperature
and enthalpy of the latter, thereby resulting in a decreased
performance of the compressor.
When the machine described in document FR 2 400 625 is configured
to operate as a turbine, a heating device can be arranged between
the low-pressure fluid passage of the first expansion stage and the
high-pressure fluid passage of the second expansion stage, so that
the fluid expanded in the first expansion stage is heated before
being conveyed toward the second expansion stage.
Such a configuration makes it possible to increase the mechanical
energy produced by the machine.
One drawback of this type of scroll machine lies, however, in the
fact that the expanded and heated fluid that is conveyed into the
second expansion stage is cooled by the expanded fluid that is
discharged from the first expansion stage, due to the proximity of
the high-pressure fluid passage of the first stage and the
low-pressure fluid passage of the second stage.
As a result, the efficiency of the scroll machine is not
optimal.
Furthermore, the scroll machine described in document FR 2 400 625
comprises a first stage extending from the outer end of the scroll
of the fixed volute casing toward the inner end of the scroll
thereof, and a second stage extending in the continuation of the
first stage as far as the inner end of the scroll of the fixed
volute casing.
Such a configuration of the two stages has the result that the
possibilities for adjusting the displacement of the second stage
are limited.
Furthermore, a significant compression rate of the first stage can
only be obtained at the expense of a significant number of scroll
turns.
The present invention aims to resolve all or part of these
drawbacks.
The technical problem at the base of the invention therefore
consists of providing a multi-stage scroll machine having a simple,
economical structure and making it possible to improve the
performance thereof, and allowing easy adjustment of the
displacements and the compression or expansion rates of the
different compression or expansion stages.
To that end, the invention relates to a multi-stage scroll machine
intended to compress and/or expand a fluid, comprising first and
second volute casings describing an orbital relative movement, the
first volute casing being equipped with at least one scroll and the
second volute being equipped with at least two scrolls, the scrolls
of the second volute casing being engaged in the scroll of the
first volute casing so as to delimit at least a first series of
variable-volume chambers belonging to a first compression or
expansion stage, and at least one second series of variable-volume
chambers belonging to a second compression or expansion stage, each
compression or expansion stage comprising at least one
high-pressure fluid passage arranged to open into at least one of
the chambers of the respective stage and at least one low-pressure
fluid passage arranged to open into at least one of the chambers of
the respective stage, the high-pressure fluid passage of the first
stage and the high-pressure fluid passage of the second stage being
configured so that the fluid passing through the high-pressure
fluid passage of the first stage has a lower pressure than that of
the fluid passing through the high-pressure fluid passage of the
second stage, characterized in that the portion of the low-pressure
fluid passage of the second stage arranged to open into at least
one of the chambers of the second stage is further from the
convergence zone of the scrolls delimiting the variable-volume
chambers of the second stage than the portion of the high-pressure
fluid passage of the second stage arranged to open into at least
one of the chambers of the first stage.
Such positioning of the low-pressure fluid passage of the second
stage significantly increases the possibilities for adjusting the
displacement and the compression or expansion rate of the different
stages, since it is no longer necessary to position the two stages
one in the extension of the other.
As a result, depending on the intermediate heating or cooling
process, it is possible, in order to improve the effectiveness and
performance of the machine, to adjust the displacements and the
compression or expansion rates of the two stages simply by adapting
the positioning of the low-pressure fluid passage of the second
stage.
Such positioning of the low-pressure fluid passage of the second
stage also makes it possible to move the latter away from the
high-pressure fluid passage of the first stage, and therefore to
avoid a heat transfer between the fluids flowing through these two
fluid passages. These arrangements make it possible to increase the
mechanical energy produced by the machine when the latter operates
as a turbine, and to easily obtain a compressed fluid having a low
discharge temperature when the machine operates as a
compressor.
It should be noted that the high-pressure fluid passage belonging
to a first compression or expansion stage can have a pressure
substantially equal to that of the low-pressure fluid passage
belonging to the second compression or expansion stage, or a
pressure substantially equal to that of the high-pressure fluid
passage belonging to the second compression or expansion stage.
Preferably, each scroll of a same volute casing extends from a same
side of said volute.
Advantageously, the scrolls of the second volute overlap one
another so that, according to at least one radial cross-section of
the second volute casing, at least one alternation of the scrolls
of the second volute casing is achieved from the convergence zone
of the scrolls of the second volute casing. It should be noted that
the convergence zone of the scrolls of the second volute casing
corresponds to the zone where the inner ends of these scrolls would
converge if the latter were extended to their origin.
It must be noted that the term "alternation of the scrolls of the
second volute casing" must be interpreted as meaning that one
successively encounters at least one first scroll of the second
volute casing, a second scroll of the second volute casing and
again the first scroll of the second volute casing.
Preferably, the variable-volume chambers of at least one of the
stages have a different height from that of the variable-volume
chambers of the other stages. Advantageously, at least one of the
scrolls of the second volute casing has a different height from
that of the other scrolls of the second volute casing. Preferably,
each scroll of the second volute casing has a different height from
that of the other scrolls of the second volute casing. These
arrangements also make it possible to adjust the displacement of
the second stage. Thus, the adjustment of the displacement of the
second stage is done primarily by adapting the position of the
low-pressure fluid passage of the second stage, and secondarily by
adjusting the relative height of the variable-volume chambers of
each stage.
Advantageously, when the mass flows seen by the different stages
are identical (typical case of an intermediate process simply
consisting of cooling or heating the fluid), the height of the
scroll of the second volute casing partially delimiting the
variable-volume chambers of the first stage is larger than the
height of the scroll of the second volute casing partially
delimiting the variable-volume chambers of the second stage.
Preferably, when the mass flow of the second stage is lower than
the mass flow of the first stage (typical case of an intermediate
process with fluid removal in compressor operation), the height of
the scroll of the second volute casing partially delimiting the
variable-volume chambers of the first stage is larger than the
height of the scroll of the second volute casing partially
delimiting the variable-volume chambers of the second stage.
When the mass flow of the second stage is greater than the mass
flow of the first stage (typical case of an intermediate process
with fluid injection in compressor mode), the height of the scroll
of the second volute casing partially delimiting the
variable-volume chambers of the first stage is advantageously
smaller than the height of the scroll of the second volute casing
partially delimiting the variable-volume chambers of the second
stage.
Preferably, the volute casing and one of the scrolls of the second
volute casing are configured so that axial play exists between the
latter parts, and said scroll of the second volute casing includes,
on its face oriented toward the first volute casing and on at least
a portion of its length, a sealing segment. The sealing between the
apex of the other scrolls and the surface of the opposite volute
casing is obtained by contact monitoring.
According to one alternative embodiment of the invention, at least
one of the scrolls of the second volute casing has a different
thickness from that of the other scrolls of the second volute
casing. Preferably, each scroll of the second volute casing has a
different thickness from that of the other scrolls of the second
volute.
According to another alternative embodiment of the invention, at
least one of the scrolls of the second volute casing has a
longitudinally variable thickness. These arrangements make it
possible on the one hand to reduce the number of turns of the
scrolls necessary for a given compression rate, and on the other
hand to produce a housing in one of the scrolls of one of the
volute casings arranged to receive one of the scrolls of the other
volute casing.
Advantageously, the machine comprises connecting means arranged to
connect the high-pressure fluid passage of the first stage and the
low-pressure fluid passage of the second stage, on the one hand,
and heating and/or cooling means arranged to heat and/or cool the
fluid flowing between the high-pressure fluid passage of the first
stage and the low-pressure fluid passage of the second stage, on
the other hand.
Advantageously, the scroll machine comprises:
a sealed enclosure delimited by a shroud whereof the upper and
lower ends are closed by a lid and a base, respectively,
a body on which the mobile volute body bears,
an electric motor surrounded by a tubular jacket defining an
intermediate chamber with the body,
a connector extending through an opening formed in the shroud and
opening into the intermediate chamber, the connector being
connected to the heating and/or cooling means, and
at least one fluid circulation passage connecting the part of the
scroll machine housing the motor to a chamber delimited by the
fixed volute casing and the lid
According to a first alternative, the low-pressure fluid passage
belonging to the second compression or expansion stage opens into
the chamber delimited by the lid and the fixed volute casing, and
the high-pressure fluid passage belonging to the first compression
or expansion stage is directly connected to a connector extending
through an opening formed in the lid, said connector being
connected to the heating and/or cooling means.
According to a second alternative, the low-pressure fluid passage
belonging to the second compression or expansion stage is connected
directly to a connector extending through an opening formed in the
lid, said connector being connected to the heating and/or cooling
means, and the high-pressure fluid passage belonging to the first
compression and/or expansion stage opens into the chamber delimited
by the lid and the fixed volute casing.
According to one embodiment of the invention, the scroll machine is
a scroll compressor, the low-pressure fluid passages of the
different stages are fluid intake passages, the high-pressure fluid
passages of the different stages are fluid discharge passages, and
the fluid is intended to be compressed successively in the first
stage and in the second stage.
Preferably, the scroll compressor comprises a coolant inlet opening
into an intake chamber formed in the body and communicating with a
suction chamber delimited by the fixed and mobile volute casings.
Advantageously, when the high-pressure fluid passage belonging to
the first compression or expansion stage is directly connected to a
connector extending through an opening formed in the lid, said
connector forms a coolant outlet, and when the low-pressure fluid
passage belonging to the second compression or expansion stage is
directly connected to a connector, said connector forms a coolant
inlet.
Preferably, at least one of the stages comprises two
variable-volume chambers, called outer chamber and inner chamber,
delimited inwardly and outwardly, respectively, by one of the
scrolls of the second volute casing and arranged to open into the
high-pressure fluid passage of the corresponding stage, and the
machine comprises pressure balancing means configured so that the
pressure in the outer chamber, before it is put in communication
with the high-pressure fluid passage of the corresponding stage, is
substantially equal to the pressure in the inner chamber before it
is put in communication with the high-pressure fluid passage of the
corresponding stage.
Advantageously, the pressure balancing means include a protrusion
extending from the inner surface of the scroll of the first volute
casing and situated at the high-pressure fluid passage of the
corresponding stage, the protrusion preferably having a profile
arranged to delay the placement of the outer chamber in
communication with the high-pressure fluid passage of the
corresponding stage. The profile of the protrusion is
advantageously the profile conjugated with that of the inner end of
the scroll of the second volute casing delimiting the outer and
inner chambers. Preferably, the protrusion has an arc-of-circle
profile with a radius equal to the orbit radius of the orbital
movement.
Advantageously, the outer end of the scroll of the first volute
casing and the outer end of the scroll of the second volute casing
partially delimiting the variable-volume chambers of the first
stage are situated asymmetrically relative to the convergence zone
of the scrolls delimiting the variable-volume chambers of the
second stage, and the balancing means include a portion of the
scroll of the first volute casing extending between a point
diametrically opposite the outer end of the scroll of the second
volute casing partially delimiting the variable-volume chambers of
the first stage relative to the convergence zone of the scrolls
delimiting the variable-volume chambers of the second stage and the
outer end of the scroll of the first volute casing.
Preferably, each scroll of the second volute casing partially
delimits the variable-volume chambers of a single stage.
According to another embodiment of the invention, the scroll
machine is a scroll expansion machine, the low-pressure fluid
passages of the different stages are fluid discharge passages, the
high-pressure fluid passages of the different stages are fluid
intake passages, and the fluid is intended to be expanded
successively in the second stage and in the first stage.
Preferably, the first volute casing is fixed and the second volute
casing is mobile.
In any event, the invention will be well understood using the
following description in reference to the appended diagrammatic
drawing showing, as a non-limiting example, two embodiments of this
scroll machine.
FIG. 1 is a diagrammatic longitudinal cross-sectional view of a
scroll machine according to a first embodiment.
FIGS. 2 and 3 are transverse cross-sectional views of the machine
of FIG. 1 showing the scrolls of the fixed and mobile volute
casings in two distinct operating positions.
FIG. 4 is a cross-sectional view along line A-A of FIG. 3.
FIG. 5 is a longitudinal cross-sectional view of the fixed and
mobile volute casings of a scroll machine according to a second
embodiment.
FIG. 6 is a transverse cross-sectional view of a scroll machine
according to a third embodiment.
FIG. 7 is a transverse cross-sectional view of the fixed and mobile
volute casings of a scroll machine according to a fourth
embodiment.
FIGS. 8 to 11 are transverse cross-sectional views of the volute
casings of FIG. 7, in four distinct operating positions
respectively offset by a quarter revolution.
FIGS. 12 to 15 are transverse cross-sectional views of the volute
casings of FIG. 7, in four distinct operating positions
respectively offset by a quarter revolution.
FIG. 16 is a transverse cross-sectional view of the fixed and
mobile volute casings of a scroll machine according to a fifth
embodiment.
FIG. 17 is a transverse cross-sectional view of the fixed and
mobile volute casings of a scroll machine according to a sixth
embodiment.
FIG. 18 is a transverse cross-sectional view of the fixed and
mobile volute casings of a scroll machine according to a seventh
embodiment.
FIG. 19 is a partial cross-sectional view of the fixed and mobile
volute casings of a scroll machine according to an eighth
embodiment.
FIG. 20 is a top view of one of the scrolls of the mobile volute
casing of FIG. 19.
FIG. 21 is a diagrammatic longitudinal cross-sectional view of a
scroll machine according to a ninth embodiment.
FIG. 22 is a diagrammatic longitudinal cross-sectional view of a
scroll machine according to a tenth embodiment.
FIGS. 1 to 4 show a multi-stage scroll machine, according to a
first embodiment of the invention, configured to operate as a
compressor arranged to compress a coolant. FIG. 1 describes a
scroll machine in a vertical position. However, the scroll machine
according to the invention could be in a tilted position, or a
horizontal position, without its structure being significantly
modified.
The scroll machine shown in FIG. 1 comprises a sealed enclosure
delimited by a shroud 2 whereof the upper and lower ends are
respectively closed by a lid 3 and a base 4. The assembly of this
enclosure can in particular be done using welding seams.
The scroll machine comprises a fixed volute casing 5 including a
plate 6 equipped with a scroll 7 intended to face downward, and a
mobile volute casing 8 including a plate 9 bearing against a body
11 contained in the jacket of the scroll machine, the plate 9 being
equipped with two scrolls 12, 13 intended to face upward.
The scroll machine comprises a drive shaft 14 whereof the upper end
is engaged in a sleeve-shaped portion 15, included in the mobile
volute casing 8. When rotated by an electric motor 16 contained in
the jacket of the scroll machine, the drive shaft 14 drives the
mobile volute casing 8 following a circular orbital movement
relative to the fixed volute casing 5.
As shown in FIG. 2, the scroll 12 of the mobile volute casing 8 has
a longitudinally variable thickness. The scroll 12 of the mobile
volute casing 8 has a first portion 12a with a constant thickness
extending from its outer end, and a second portion 12b with a
variable thickness extending in the continuation of the first
portion 12a and as far as the inner end of the scroll 12.
The scroll 13 of the mobile volute casing 8 has a constant
thickness.
It should be noted that the scrolls 12, 13 of the mobile volute
casing 8, if they were extended as far as their origin, would
converge toward a convergence zone situated substantially at the
center of the mobile volute casing 8.
The scrolls 12, 13 of the mobile volute casing 8 overlap one
another so that, according to at least one radial cross-section of
the mobile volute casing 8, one encounters, from the convergence
zone of the scrolls 12, 13, the scrolls 12, 13, alternatingly, of
the mobile volute casing 8.
The scroll 7 of the fixed volute casing 5 has a longitudinally
variable thickness. The scroll 7 of the fixed volute casing 5 has a
first portion 7a with a constant thickness extending from its outer
end, and a second portion 7b with a variable thickness extending in
the continuation of the first portion 7a and as far as the inner
end of the scroll 7.
The second portion 7b of the scroll 7 of the fixed volute casing
comprises a housing 17 extending in a scroll arranged to receive
the scroll 13 of the mobile volute casing 8.
As shown in FIG. 4, the scrolls 12, 13 of the mobile volute casing
8 and the scroll 7 of the fixed volute casing have an identical
height.
The scrolls 12, 13 of the mobile volute casing 8 are engaged in the
scroll 7 of the fixed volute casing 5 so as to delimit a first
series of variable-volume chambers 18a to 18d belonging to a first
compression stage, and a second series of variable-volume chambers
18e to 18h belonging to a second compression stage.
The scroll 12 of the mobile volute casing 8 partially delimits only
the variable-volume chambers 18a to 18d belonging to the first
compression stage, while the scroll 13 of the mobile volute casing
8 partially delimits only the variable-volume chambers 18e to 18h
belonging to the second compression stage.
Each compression stage comprises pairs of variable-volume
compression chambers respectively delimited inwardly and outwardly
by one of the scrolls of the mobile volute casing 8, the
compression chambers having a volume that decreases gradually from
the outside in during the orbital movement of the mobile volute
casing 8.
It should be noted that the scroll 7 of the fixed volute casing 5
and the scroll 13 of the mobile volute casing 8 converge toward a
convergence zone situated substantially at the center of the fixed
volute casing.
The outer end of the scroll 7 of the fixed volute casing 5 and the
outer end of the scroll 12 of the mobile volute casing 8 are
situated symmetrically relative to the convergence zone of the
scrolls 7, 13 delimiting the variable-volume chambers of the second
stage.
The first compression stage comprises two fluid intake passages
19a, 19b connected to a coolant inlet 21 formed radially in the
shroud 2 via two intake channels 22 formed in the body 11, on the
one hand, and a suction chamber 23 delimited by the fixed 5 and
mobile 8 volute casings and communicating with the two intake
channels 22, on the other hand.
The fluid intake passage 19a is delimited by a space between the
outer end of the scroll 7 of the fixed volute casing 5 and the
outer wall of the scroll 12 of the mobile volute casing 8. The
fluid intake passage 19b is delimited by a space between the outer
end of the scroll 12 of the mobile volute casing 8 and the outer
wall of the scroll 7 of the fixed volute casing 5.
The fluid intake passages 19a, 19b are arranged to emerge
respectively in the outermost variable-volume chambers of the first
stage (chambers 18a and 18b in FIG. 2) during the orbital movement
of the mobile volute casing 8.
The first compression stage also comprises a fluid discharge
passage 24 arranged to open respectively into the innermost
variable-volume chambers of the first stage (chambers 18c, 18d in
FIG. 2) during the orbital movement of the mobile volute casing
8.
The fluid discharge passage 24 of the first stage is formed by a
through orifice formed in the plate 6 of the fixed volute casing 5
and opening at the inner end of the scroll 12 of the mobile volute
casing 8. The through orifice 24 is directly connected to a coolant
outlet 25 formed in the lid 3. The coolant outlet 25 advantageously
extends parallel to the axis of the machine.
The second compression stage comprises a fluid intake passage 26
connected to a coolant inlet 27 formed in the lid 3 and arranged to
open respectively into the outermost chambers of the second stage
(chambers 18e and 18f in FIG. 2) during the orbital movement of the
mobile volute casing 8.
The second compression stage also comprises a fluid discharge
passage 28 arranged to open respectively into the innermost
chambers of the second stage (chambers 18g and 18h in FIG. 2)
during the orbital movement of the mobile volute casing 8.
The fluid intake passage 26 is formed by a through orifice formed
in the plate 6 of the fixed volute casing 5 and opening at the
outer end of the scroll 13 of the mobile volute casing 8. The fluid
discharge passage 28 of the second stage is formed by a through
orifice formed in the plate 6 of the fixed volute casing 5 and
emerging at the inner end of the scroll 13 of the mobile volute
casing 8. The through orifice 28 is connected to a coolant outlet
29 radially formed in the lid 3 via a discharge chamber 31
delimited by the lid 3 and the fixed volute casing 5.
Preferably, the intake 26 and discharge 28 orifices of the second
stage and the discharge orifice 24 of the first stage extend
substantially perpendicular to the plate 6 of the fixed volute
casing 5.
As shown in FIG. 2, the fluid intake orifice 26 of the second
compression stage is further from the center of the fixed volute
casing 5 than the discharge orifice 24 of the first compression
stage. It should also be specified that the fluid intake orifice 26
of the second compression stage is further from the convergence
zone of the scroll 7 of the fixed volute casing 5 and the scroll 13
of the mobile volute casing 8 than the discharge orifice 24 of the
first compression stage.
The scroll machine also comprises connecting means arranged to
connect the fluid discharge passage 24 of the first stage to the
fluid intake passage 26 of the second stage, and on the other hand
the cooling means 33 arranged to cool the fluid flowing from the
fluid discharge passage 24 of the first stage to the fluid intake
passage 26 of the second stage. The connecting means include,
according to the embodiment shown in FIG. 1, the coolant outlet 25,
the coolant inlet 27 and two connecting portions 32 respectively
connecting the coolant outlet 25 to the cooling means 33 and the
coolant inlet 27 to the cooling means 33.
The operation of the scroll machine will now be described.
FIG. 3 shows a position of the fixed 5 and mobile 8 volute casing
in which the two outer compression chambers of the first
compression stage are respectively closed at the outer ends of the
scrolls 7 and 12. This position of the fixed 5 and mobile 8 volute
casing corresponds to the so-called "displacement" position.
Once the mobile volute casing 8 moves from the position shown in
FIG. 3, the outer chambers of the first stage move toward the
inside in the clockwise direction and their capacity decreases,
which causes a compression of the coolant contained in the latter
parts. When these two outer chambers reach the discharge orifice
24, the coolant contained in the latter parts is discharged through
said discharge orifice 24 and is transported to the cooling means
33 via the coolant outlet 25 and one of the connecting portions
32.
The compressed coolant is cooled and is then transported to the
intake orifice 26 of the second stage via the other connecting
portion 32 and the coolant inlet 27, so it can be compressed in the
variable-volume chambers of the second stage and so it can be
discharged through the discharge orifice 28 formed substantially at
the center of the fixed volute casing 5.
FIG. 5 shows an alternative embodiment of the scroll machine that
differs from that shown in FIG. 1 in that the scroll 13 of the
mobile volute casing 8 has a height h2 greater than the height h1
of the scroll 12 of the mobile volute casing 8 so that the
variable-volume chambers belonging to the second compression stage
have a height greater than that of the variable-volume chambers
belonging to the first compression stage.
FIG. 6 shows an alternative embodiment of the scroll machine that
differs from that shown in FIG. 1 in that it also comprises
pressure balancing means configured so that the pressure in the
variable-volume chamber 18c before it is put in communication with
the fluid discharge passage 24 of the first stage is substantially
equal to the pressure in the variable-volume chamber 18d before it
is put in communication with the fluid discharge passage 24 of the
first stage.
The balancing means include a protrusion 34 extending from the
inner surface of the scroll 7 of the fixed volute casing 5 and
situated at the fluid discharge passage 24 of the first stage. The
protrusion 34 has an arc-of-circle profile 35 arranged to delay the
placement of the variable-volume chamber 18c in communication with
the fluid discharge passage 24 of the first stage.
As shown in broken lines in FIG. 6, the outer end of the scroll 7
of the fixed volute casing and the outer end of the scroll 12 of
the mobile volute casing could be situated substantially
asymmetrically relative to the convergence zone of the scrolls 7,
13 delimiting the variable-volume chambers of the second stage.
According to this embodiment, the balancing means would also be
made up of a portion 36 of the scroll 7 extending between a point
diametrically opposite the outer end of the scroll 12 of the mobile
volute casing relative to the convergence zone of the scrolls 7, 13
and the outer end of the scroll 7 of the fixed volute casing.
FIG. 7 shows another alternative embodiment of the scroll machine
that differs from that shown in FIG. 1 essentially in that the
fixed volute casing 5 comprises two scrolls 7, 7' overlapping one
another and the inner ends of which are connected to one another by
a partition 40, in that the scrolls 12, 13 of the mobile volute
casing 8 have an identical constant thickness, and in that the
first stage includes only one fluid intake passage 19.
The fluid intake passage 19 is delimited by the outer end of the
scroll 7 of the fixed volute casing 5 and the outer wall of the
scroll 7' of the fixed volute casing 5, and is arranged to open
respectively into the outermost variable volute chambers of the
first stage (chambers 18a and 18b in FIG. 7) during the orbital
movement of the mobile volute casing.
The scrolls 7, 7' of the fixed volute casing 5 overlap one another
so that, according to a radial cross-section of the fixed volute
casing 5, one encounters, from the convergence zone of the scrolls
7, 7', alternatively the scrolls 7, 7' of the fixed volute casing
5. The scrolls 7, 7' of the fixed volute casing 5 have an identical
constant thickness.
The outer end of the scroll 7' of the fixed volute casing 5 is
connected to the outer wall of the scroll 7 of the fixed volute
casing 5 at the intake orifice 26 of the second stage.
The scrolls 12, 13 of the mobile volute casing 8 are engaged in the
scrolls 7, 7' of the fixed volute casing 5 so as to delimit a first
series of variable-volume chambers 18a to 18d belonging to a first
compression stage, and a second series of variable-volume chambers
18e to 18h belonging to a second compression stage.
FIG. 8 shows the scrolls of the fixed and mobile volute casings of
FIG. 7 in angular positions such that the outer end of the scroll
12 of the mobile volute casing 8 defines a sealing line of one of
the chambers of the first stage.
Points A to E shown in FIG. 8 show the sealing lines between the
scroll 12 of the mobile volute casing 8 and the scrolls of the
fixed volute casing 5, these sealing lines defining the
variable-volume chambers of the first stage.
FIGS. 9 to 11 show three distinct operating positions of the scroll
machine respectively offset by a quarter revolution relative to the
position shown in FIG. 8. These different figures make it possible
to view the evolution of the variable-volume chambers 18a to 18d of
the first stage and points A to E during the orbital movement of
the mobile volute casing 8.
FIG. 12 shows the scrolls of the fixed and mobile volute casings of
FIG. 7 in angular positions so that the outer end of the scroll 13
of the mobile volute casing 8 defines the sealing line of one of
the chambers of the second stage.
Points F to I shown in FIG. 12 show the sealing lines between the
scroll 13 of the mobile volute casing 8 and the scrolls of the
fixed volute casing 5, these sealing lines defining the
variable-volume chambers of the second stage.
FIGS. 13 to 15 show three distinct operating positions of the
scroll machine respectively offset by a quarter revolution relative
to the position shown in FIG. 12. These different figures make it
possible to view the evolution of the variable-volume chambers 18e
to 18h and points F to I during the orbital movement of the mobile
volute casing 8.
FIG. 16 shows another alternative embodiment of the scroll machine
that differs from that shown in FIG. 7 in that the outer end of the
scroll 7 of the fixed volute casing 5 is connected to the outer
wall of the scroll 7' of the fixed volute casing 5, and in that the
first stage comprises a single fluid intake passage 19 constituted
by a through orifice formed in the plate 6 of the fixed volute
casing 5 and emerging at the outer end of the scroll 7 of the fixed
volute casing 5. The through orifice 19 is arranged to open
respectively into the outermost variable-volute chambers of the
first stage during the orbital movement of the mobile volute.
FIG. 17 shows another alternative embodiment of the scroll machine
that differs from that shown in FIG. 16 in that the scroll 12 of
the mobile volute casing 8 has a smaller thickness than that of the
scroll 13 of the mobile volute casing 8.
FIG. 18 shows another alternative embodiment of the scroll machine
that differs from that shown in FIG. 17 in that the scroll 7 of the
fixed volute casing 5 has a thickness smaller than that of the
scroll 7' of the fixed volute casing 5.
FIG. 19 shows still another alternative embodiment of the scroll
machine that differs from that shown in FIG. 1 in that the fixed
volute casing 5 and the scroll 13 of the mobile volute casing 8 are
configured so that axial play Ja exists between the latter, and in
that the scroll 13 of the mobile volute casing 8 includes, on its
face oriented toward the plate 6 of the fixed volute casing, a
sealing segment 42.
As shown in FIG. 20, the sealing segment 42 extends only over the
central portion of the scroll 13 of the mobile volute casing 8.
According to one alternative embodiment of the scroll machine not
shown in the figures, the sealing segment 42 could extend over the
entire length of the scroll 13 of the mobile volute casing.
According to still another alternative embodiment of the scroll
machine not shown in the figures, the scroll 7 of the fixed volute
casing 5 could also comprise, on its face oriented toward the plate
9 of the mobile volute casing 8, a sealing segment.
FIG. 21 shows still another alternative embodiment of the scroll
machine that differs from that shown in FIG. 1 in that the coolant
inlet 21 opens into an intake chamber 43 formed in the body 11 and
communicating with the suction chamber 23 delimited by the fixed 5
and mobile 8 volute casings, in that the fluid intake passage 26
opens into a chamber 44 delimited by the lid 3 and the fixed volute
casing 5, in that the coolant outlet 29 extends substantially
parallel to the axis of the scroll machine, in that the fluid
discharge passage 28 is directly connected to the coolant outlet
29, and in that the scroll machine comprises a connector 45
extending radially through the shroud 2 and opening into an
intermediate chamber 46 delimited by the body 11, the motor 16 and
a tubular jacket 47 surrounding the latter, the connector 45 being
connected to the cooling means 33.
Under operating conditions of the scroll machine shown in FIG. 21,
the compressed coolant discharged by the discharge orifice 24 is
transported to the cooling means 33 via the coolant outlet 25 and
one of the connecting portions 32.
The compressed fluid is cooled and is then transported to the
connector 45 via the other of the connecting portions 32. The
coolant passes into the intermediate chamber 46 and flows from top
to bottom through the motor 16, in particular through a space
situated between the rotor and the stator thereof. The coolant then
flows from bottom to top in the annular volume 48 delimited by the
tubular jacket 47 and the shroud 2 as far as the chamber 44 via at
least one peripheral passage 49 formed between the shroud 2 and the
body 11. The coolant then reaches the intake orifice 26 of the
second stage, so it can be compressed in the variable-volume
chambers of the second stage.
Such a circulation of the coolant between the two compression
stages improves the cooling of the motor, since the latter is
cooled by a higher-density gas. Furthermore, as a result of such a
circulation of the coolant between the two compression stages, the
part of the scroll machine housing the motor 16 is at a pressure
substantially identical to that of the coolant discharged by the
discharge orifice 24 of the first compression stage, therefore at a
greater pressure relative to the embodiment shown in FIG. 1. This
results in a decrease in the pressure difference between the
peripheral chambers of the second stage and the part of the scroll
machine housing the motor 16, which makes it possible to reduce
leaks between these peripheral pockets of the second stage and the
part of the scroll machine housing the motor 16. This decrease in
the pressure difference between the peripheral chambers of the
second stage and the part of the scroll machine housing the motor
16 also makes it possible to limit the forces exerted on the plate
of the mobile volute casing, therefore to limit the wear of the
latter.
Furthermore, such a circulation of the coolant between the
compression stages improves the volumetric and isentropic output of
the scroll machine because the coolant flows directly into the
first compression stage, without being deteriorated by its passage
through the motor 16.
FIG. 22 shows still another embodiment of the scroll machine that
differs from that shown in FIG. 21 in that the fluid intake passage
24 opens into the chamber 44 delimited by the lid 3 and the fixed
volute casing 5, and in that the fluid intake passage 26 is
connected to a coolant inlet 27 formed in the lid 3.
Under operating conditions of the scroll machine shown in FIG. 22,
the compressed coolant discharged by the discharge orifice 24
enters the chamber 44 delimited by the lid 3 and the fixed volute
casing 5, and flows from top to bottom in the annular volume 48
delimited by the tubular jacket 47 and the shroud 2 via the
peripheral passage 49. The coolant then flows from bottom to top
through the motor 16, as far as the intermediate chamber 46. Then,
the coolant is transported as far as the cooling means 33 via the
connector 45 and one of the connecting portions 32.
The compressed coolant is cooled and is then transported as far as
the intake orifice 26 of the second stage via the other of the
connecting portions 32 and the coolant inlet 27.
Such a circulation of coolant between the two compression stages
improves the cooling of the engine, since the latter is cooled by a
higher-density gas, and previously cooled.
According to one embodiment of the invention not described in the
figures, the scroll machine could be configured to operate as a
scroll expansion machine, like a scroll turbine. In that case, the
intake passages would be discharge passages, the discharge passes
would be intake passages, and the coolant would be intended to be
expanded successively in the second stage and in the first
stage.
The invention is of course not limited to only the embodiments of
this scroll machine described above as examples, but on the
contrary encompasses all alternative embodiments.
* * * * *